The publications and other materials used herein to illuminate the background of the invention, and in particular, cases to provide additional details respecting the practice, are incorporated by reference.
Lignans are phenolic-compounds widely distributed in plants. They can be found in different parts (roots, leafs, stem, seeds, fruits) but mainly in small amounts. In many sources (seeds, fruits), lignans are found as glycosidic conjugates associated with fiber component of plants. The most common dietary sources of mammalian lignan precursors are unrefined grain products. The highest concentrations in edible plants have been found in flaxseed, followed by unrefined grain products, particularly rye.
Considerable amounts of lignans are also found in coniferous trees. The type of lignans differs in different species and the amounts of lignans vary in different parts of the trees. The typical lignans in heartwood of Norway spruce (Picea abies) are hydroxymatairesinol (HMR), alpha-conidendrin, alpha-conidendric acid, matairesinol, isolariciresinol, secoisolariciresinol, liovil, picearesinol, lariciresinol and pinoresinol (Ekman R: Distribution of lignans in Norway spruce. Acta Academiae Aboensis, Ser B, 39:1-6, 1979).
The far most abundant single component of lignans in spruce is HMR, about 60 percent of total lignans, which occurs mainly in unconjugated free form. Plant lignans such as hydroxymatairesinol, matairesinol, lariciresinol and secoisolariciresinol, are converted by gut microflora to mammalian lignans, enterolactone or enterodiol. The mammalian lignans can also be manufactured synthetically (M B Groen and J Leemhius, Tetrahedron Letters 21, 5043, 1980).
Lignans are known to possess beneficial effects on human health. The health benefits obtained with lignan rich diet are, for example, decreased risk for various cancers and cardiovascular diseases (Adlercreutz (1998) Phytoestrogens and human health, In: Reproductive and Developmental Toxicology (edited by Korach, K.). pp. 299-371, Marcel & Dekker, NY.).
Lignans, such as hydroxymatairesinol, WO 00/59946, have also been reported to inhibit lipid peroxidation and LDL oxidation and thus be useful as antioxidants.
Also lignans other than hydroxymatairesinol have powerful antioxidant and anti-inflammatory potential. The antioxidant action involves all the major free radicals such as superoxide anions and peroxyl radicals (K Prasad: Antioxidant activity of secoisolariciresinol diglucoside-derived metabolites, secoisolariciresinol, enterodiol and enterolactone. Int J Angiology 9:220-225 (2000)).
According to studies, lignans may also prevent skin cancers (Thompson L. U. (1993): Potential health benefits and problems associated with antinutrients in foods. Food Res. Int. 26, 131-149).
No topical preparations, either for cosmetic or pharmaceutical use, comprising lignans, especially lignans which can be derived from wood in great quantities, or lignans or lignan derivatives, such as phenolic esters, manufactured from such wood-derivable lignans, have been described in the art.